YouTube not playing

I have a MacBook Pro running High Sierra and when I go to Youtube and click on any video, nothing happens. When I go to the same Youtube video in Safari, it plays. It's really annoying having to cut and paste from one browser to another in order to watch a Youtube video . Trying to make Opera my default browser, but behavior like this is preventing me from doing so.

I may have found a solution to my own problem.
I just updated Opera to v. 49.
If I now go to Youtube, right click on a video, and chose to open it in another tab, the video immediately opens and plays.